Re: Well, I thought I had everything picked out, then I came here...
I'd definitely scrap the Kenwood amps. As for the headunit, definitely scratch the Sony. I've only used a Kenwood before and I will agree their UI is exceptionally difficult. But once I got it down, and understood everything, it's a breeze to get through. I've just ordered a new Kenwood x-994, which should be here today. x995 was my second choice and looks good to me, and I've heard great things from it. I think it'll be a good choice for ya man. I was also looking at this one: Buy Kenwood KDC-BT948HD In-Dash USB/CD Receiver with Built-in Bluetooth & HD Radio for $224.95
BnG makes a good point on using a processor and keeping your factory HU, definitely an option, and for ultimate clarity and tuning. Also, using a good 5-channel amp. On a budget I'd recommend the eD 9.5: Elemental Designs: Car Stereo, Home Speakers, Electronics
That sale is long done, but they are available in b-stock from their forum for $350 shipped. Great underrated amps, clean, no BS. I run a couple of their other ones and I am very happy with them.
Cheaper, cleaner, lower powered subs?
SSA Dcon: Sub Woofers - SoundSolutionsAudio - DCON - SSA STORE
Dayton Reference: Dayton Audio RSS265HF-4 10" Reference HF Subwoofer 4 Ohm 295-460
IA 187: Sub Woofers - Incriminator Audio - 187 - SSA STORE
Skar: Sub Woofers - Skar Audio - SSA STORE
TC Sounds Epic: TC Sounds Epic 10" DVC Subwoofer 293-656
Depending on how much power you want to run on your Sub-stage. Most of those will perform very well in a smaller sealed enclosure, and I'd probably go with a 10 or 12 if you're going sealed. If you're willing to give up just a bit of space, a ported 8" would be great. Skar and TC Sounds make some pretty beast 8's.
I run 1200+w to my sub, and have 300w on my front stage and I can hear my front speakers at all volumes, clear and clean, no problem. The sub doesn't drown it out because it's tuned properly.
The Kenwood speakers I'd scrap as well. I've owned a pair and am not impressed. If you get 6x8 to 6.5 speaker adapter rings, you'll have a lot more options on better components and coaxials for front and rear.
2009 Hyundai Elantra - Budget Sound in Progress
HU- Kenwood eXcelon KDC-X994
Fronts- Crescendo MP6 mids, Vifa Ring Radiator tweets on Arc KS300.4
Subs- Single SA-10 on Mmats 2000.1 @ 1ohm
Misc- 1/0 CCA from AT, Big 3 in Stinger HPM, and AT 60 mil deadener
Bought from: Inferno333, select127, treesive, Kangaroux, DonH
Sold to: coolest user, Psychodrama, MidgetClown, mr.tigger, av83